A method for fabricating probes on a probe head is disclosed in the U.S. Pat. No. 5,513,430 entitled “METHOD FOR MANUFACTURING A PROBE”, as shown in FIG. 1. The probe head 10 comprises a substrate 11 having an upper surface 12 and a lower surface 13. The substrate 11 could be made of FR-4, bismaleimide triazine(BT), and the like. Substrate 11 are extended through by metal filled vias 14, wherein one end 17 of each metal filled via 14 may terminate at surface 12 and a second end 18 of each metal filled via 14 may terminate at surface 13. Contact pads 19 are fabricated on the surface 12 and in contact with ends 17. Likewise, contact pads 21 are fabricated on the surface 13 and in contact with second ends 18. The contact pads 21 are for conducting feedouts or electrical interconnects, while the contact pads 19 are for fabricating probes 56 by electroplating, as shown in FIG. 2.
As shown in FIG. 1, the probe head 10 having a plating base 22 fabricated on the upper surface 12 and contact pads 19. Plating base 22 comprises an adhesion layer 20 and a plating seed layer 24. The adhesion layer 20 is made of titanium, chromium, and the like, whereas the plating seed layer 24 is made of gold, nickel, and the like. Then the resist layer 45 is coated on the plating base 22. In addition, a UV mask 41 and a UV radiation light source 42 are also needed. The UV radiation mask 41 comprises a thin quartz plate 43 having a patterned layer of chromium 44 disposed thereon. UV radiation is capable of traveling through the quartz plate 43 but is absorbed by chromium layer 44. Chromium layer 44 is patterned to have openings 47 through which UV radiation 48 travels and irradiates the portions of resist layer 45. A plurality of openings are fabricated, and then it was proceeded to fabricate a portion 51 of probes 56 by electroplating. The second resist layer 46 was fabricated on the first barrier layer 45 by lithography. At this time, it only needed to move the UV mask 41 according to the needed fabricate of probes 56 to fabricate openings 49 on the second barrier layer, and then again it was proceeded to fabricate a portion 52 of probes 56 by electroplating. Steps of fabricating the portions of probes 56 were repeated until probes 56 were fabricated.
FIG. 2 referred to a method to fabricate a probe card 55. While probes 56 were fabricated on the probe head 10, the barrier layer and plating base 22 were then removed to fabricate a probe card 55. Each of the probes 56 of the probe card 55 comprises the portions of 51, 52, and 53. The portions of 51, 52, and 53 were fabricated according to the hardness or conductivity of probes by electroplating metals selected from the group of nickel, gold, copper, palladium, tin, etc. Probes 56 are in stair-step shaped, and are elastic and compliant of the bonding pads on a semiconductor chip. This advantage permits to decrease the contact resistance and scrubbing on chips. Yet the manufacturing method mentioned above also has disadvantages. It needed to fabricate a barrier layer 45 by lithography before electroplating, and then to irradiate by a UV radiation source 42 and a UV mask 41. A plurality of openings were fabricated on the barrier layer 45, and then it proceeded to fabricate portion 51 of probes 56 by electroplating. The steps were repeated to fabricate portions of 52, and 53, but only simple shape such as a stair-step shaped or single angle probes 56 could be fabricated. Also there is stress concentrated in the interfaces of portions of 51, 52, and 53 while probing. The manufacturing method mentioned above needs to repeat steps such as fabrication of barrier layers, irradiation of UV, and the like until probes 56 are fabricated. It also needs to design different fabrication of UV masks according to the shapes of probes. All of these contribute to increase the manufacturing processes, time and also the costs.